fix(aur): Use newest xpp commit to build with xcb-proto
fix(aur): Use newest xpp commit to build with xcb-proto

xcb-proto 1.13 finally introduces the eventstruct key that made polybar
not compile. The fix isn't in any release yet, this checks out the
newest xpp commit with the fix during compilation until we release 3.2.0

Fixes #1090

jaagr/polybar,jaagr/lemonbuddy,jaagr/polybar,jaagr/lemonbuddy,jaagr/polybar,jaagr/lemonbuddy